JP6532079B2 - Method of estimating initial creep strength of heat resistant member and method of estimating remaining life thereof - Google Patents

Description

  The present invention relates to a method of estimating the initial creep strength of a heat-resistant member and a method of estimating the remaining life thereof.

  Heretofore, in various plants used under high temperature and high pressure environments, it is known that creep damage progresses with the passage of operation time, and the life is consumed. Therefore, in order to maintain sound operation in the various plants, it is necessary to accurately estimate the remaining life of the device and replace the device at an appropriate time. Various methods for evaluating the remaining life of the device have been studied.

  For example, in Patent Document 1 below, stress based on hardness is used to sequentially read steady operation state data from the operation result information storage unit, and based on this, the operation history calculation unit obtains member temperature and member stress, and further Calculate the amount of increase in stress in each operating state, calculate the amount of decrease in creep strength due to the increase in stress, calculate creep strength, determine the current member hardness, and calculate the amount of decrease in creep strength based on planned operation state data. A life diagnosis method of a high temperature member is described which calculates a final predicted value of creep strength after calculating creep strength, and calculates a remaining life based on the predicted value and planned operating conditions.

JP, 2013-57546, A

  By the way, in the evaluation of the remaining life of the device, the initial creep strength of the member subject to life evaluation is an important factor, but in the case of an aged plant, the initial creep strength of the member may not be grasped. In such a case, the remaining life of the device could not be accurately estimated. Therefore, it has been desired to estimate the initial creep strength and the remaining life of the existing members by a simple and quick method.

  From the above, the present invention has been made to solve the above-mentioned problems, and a heat-resistant member capable of rapidly estimating the initial creep strength and the remaining life of the heat-resistant member by a relatively simple operation. It is an object of the present invention to provide an initial creep strength estimation method and this residual life estimation method.

The method for estimating the initial creep strength of a heat resistant member according to the first aspect of the present invention for solving the above-mentioned problems is a method for estimating the initial creep strength of a heat resistant member, and the heat resistant member is subjected to a creep test at a predetermined temperature and stress. Based on the rupture time acquisition process of acquiring the fracture time, the rupture time of the heat-resistant member and the predetermined temperature, the Larson mirror parameters at fracture derived using the following relational expression (1) The creep strength line of the heat resistant member based on the derivation step, the design creep strength diagram showing the relationship between the Larson mirror parameter at break and the Larson mirror parameter as initial data of the heat resistant member and the stress in the heat resistant member The creep strength diagram acquisition process of the heat-resistant member to obtain the figure and the equivalent average operating temperature from the carbide state of the heat-resistant member Equivalent average operating temperature estimating step of constant, the a creep strength diagram of heat-resistant member, and the equivalent average operating temperature, based on the known operating stresses, of the heat-resistant member using the following equation (1) A remaining life deriving step for deriving a remaining life, an entire life deriving step for deriving an entire life of the heat resistant member based on a remaining life of the heat resistant member, and an operation time of the heat resistant member; An all-life Larson mirror parameter deriving step of deriving an all-life Larson mirror parameter using the following relation (1) based on the equivalent average operating temperature, and the designed creep strength line based on the all-life Larson mirror parameter And an initial creep strength diagram deriving step of deriving an initial creep strength diagram of the heat-resistant member using a figure.
LMP = T × (C + log (t)) / 1000 (1)
LMP is a Larson mirror parameter, T is an absolute temperature (K), C is a material constant of the heat resistant member, and t is an operation time of the heat resistant member.

  The method for estimating the initial creep strength of a heat resistant member according to the second invention for solving the above-mentioned problems is the method for estimating the initial creep strength of a heat resistant member according to the first invention, wherein the equivalent average operating temperature estimation step A replica to which the surface structure of the heat-resistant member is transferred is created, a carbide image is created based on the replica, a carbide amount is derived based on the carbide image, the carbide amount, the carbide amount previously prepared, and the Larson mirror parameters The present Larson mirror parameters are derived using the master curve which is a correlation diagram of the above, and based on the present Larson mirror parameters and the operation time of the heat-resistant member, the equivalent average is calculated using It is characterized in that the operating temperature is estimated.

  The method for estimating the initial creep strength of a heat resistant member according to the third invention for solving the above-mentioned problems is the method for estimating the initial creep strength of a heat resistant member according to the second invention, wherein the carbide image is an image of primary carbides. It is characterized by being an image of a certain or secondary carbide, or an image of a primary carbide and an image of a secondary carbide.

  The method for estimating the initial creep strength of a heat resistant member according to the fourth invention for solving the above-mentioned problems is the method for estimating the initial creep strength of a heat resistant member according to the second or third invention, wherein the amount of carbide is carbide It is characterized in that it is at least one of particle number density or area ratio of carbide.

  The method for estimating the initial creep strength of a heat-resistant member according to the fifth invention for solving the above-mentioned problems is the method for estimating the initial creep strength of a heat-resistant member according to any one of the second to fourth inventions The Larson mirror parameters may be derived using the amount of carbide derived based on the carbide binarized image created by binarizing the carbide image and using the master curve instead of the carbide image. It features.

  The method for estimating the initial creep strength of a heat-resistant member according to a sixth aspect of the present invention for solving the above-mentioned problems is the method for estimating the initial creep strength of a heat-resistant member according to any one of the first to fifth aspects Is characterized in that it is a catalyst tube used for reforming natural gas.

The remaining life estimating method of the heat resistant member according to the seventh invention for solving the above-mentioned problems is a remaining life estimating method of the heat resistant member for estimating the remaining life of the heat resistant member, and the current heat resistant member is operated by the nondestructive test. The heat input received inside is derived as a Larson mirror parameter, and the equivalent average operating temperature is estimated using the following relational expression (2) based on the current Larson mirror parameter of the heat-resistant member and the known operation time And the initial creep strength of the heat resistant member derived by the method of estimating the initial creep strength of the heat resistant member according to any one of the first to fifth inventions, and the known operating stress. Based on the above, the overall life is derived using the following relational expression (2), and the remaining life is derived based on the overall life and the operating time of the heat-resistant member.
LMP = T × (C + log (t)) / 1000 (2)
LMP is the present Larson mirror parameter of the heat resistant member, T is the equivalent average operating temperature (absolute temperature (K)), and t is the operating time (total life).

  The remaining life estimation method of a heat resistant member according to the eighth invention for solving the above-mentioned problems is the remaining life estimation method of a heat resistant member according to the seventh invention, wherein the heat resistant member is used for reforming natural gas And a catalyst tube.

  According to the present invention, the initial creep strength and the remaining life of the heat-resistant member can be rapidly estimated by a relatively simple operation.

It is a flowchart for demonstrating the procedure of the initial stage creep strength estimation method of the heat-resistant member which concerns on 1st embodiment of this invention. It is a graph which shows the relationship of the Larson mirror parameter and stress which are used by the initial stage creep strength estimation method of the said heat-resistant member. It is a flowchart for demonstrating an example of the procedure which derives | requires the remaining life of the said heat-resistant member. FIG. 4 (a) is a graph showing the relationship between the amount of carbide and the Larson mirror parameter created in the procedure for deriving the remaining life, and FIG. 4 (a) shows the relationship between the particle number density of carbide and the Larson mirror parameter; b) shows the relationship between the area fraction of carbide and the Larson mirror parameters. It is the schematic of the catalyst pipe | tube which is an example of evaluation object of the initial stage creep strength estimation method of the said heat-resistant member. It is a flowchart for demonstrating the procedure of the remaining life evaluation method of the heat-resistant member which concerns on 2nd embodiment of this invention. It is a graph which shows the relationship of the Larson mirror parameter and stress which were created by the confirmatory test of the initial stage creep strength estimation method of the heat-resistant member which concerns on the Example of this invention.

  The embodiments of the method for estimating the initial creep strength of a heat resistant member and the method for estimating the remaining life according to the present invention will be described based on the drawings, but the present invention is limited to the following embodiments described based on the drawings. is not.

First Embodiment
The method for estimating the initial creep strength of a heat-resistant member according to the first embodiment of the present invention will be described based on FIGS. 1 to 5.
In the present embodiment, the case where the present invention is applied to a plurality of catalyst tubes consisting of, for example, several hundreds connected to each of a plurality of hot collectors provided in a natural gas reformer will be described.

  For example, as shown in FIG. 5, the natural gas reformer includes a plurality of catalyst tubes 14 each including a catalyst tube body 11, a short piece 12, and a pigtail 13. The catalyst tube main body 11 is vertically disposed so that the axial center extends in the vertical direction. The short piece 12 is connected to the lower end portion of the catalyst tube main body 11, and is vertically disposed so that the axial center extends in the vertical direction. The pigtail 13 is connected to the lower end portion of the short piece 12 and has a smaller diameter than the catalyst tube main body 11 and is disposed so as to be bent. The other end of the pigtail 13 is connected to the hot collector 15. The hot collector 15 is disposed such that the axial center extends in the horizontal direction (in the illustrated example, in the front and back direction in the drawing). The other end of the pigtail of the catalyst pipe (not shown) is connected to the hot collector 15 at a position symmetrical with the catalyst pipe 14. Furthermore, a pair of left and right catalyst tubes connected to the hot collector 15 are disposed at predetermined intervals in the axial direction of the hot collector 15. The natural gas reformer is provided with a plurality of hot collectors 15 to which a plurality of catalyst tubes 14 are connected.

  The catalyst tube body 11, the short piece 12, and the pigtail 13 are made of, for example, HP-Nb-Ti (25Cr-35Ni-Nb, Ti) and Alloy 800H (Fe-32Ni-20Cr). The catalyst tube main body 11 reacts with the introduced mixed gas (methane gas, water vapor) 21 to generate a product gas (hydrogen, water vapor, carbon monoxide, carbon dioxide) 22. The generated gas 22 is circulated to the hot collector 15 through the short piece 12 and the pigtail 13.

  The catalyst tube main body 11 is disposed in a furnace of about 900 ° C. or higher. Although the short piece 12 and the pigtail 13 are disposed outside the furnace, a gas of about 900 ° C. flows through the inside.

  The method for estimating the initial creep strength of a heat-resistant member according to the present embodiment is, as shown in FIG. 1, a step S1 of heat-resistant member creep test (acquisition of fracture time at test temperature and stress) and step of deriving Larson mirror parameters at break of heat-resistant member S2, creep strength diagram acquisition step S3 of heat resistant member, equivalent average operating temperature estimation step S4, remaining life deriving step S5, overall life deriving step S6, overall life Larson mirror parameter deriving step S7, initial creep And a strength diagram drawing step S8.

  In the heat-resistant member creep test step S1, the rupture time of the catalyst pipe main body 11 (the aged heat-resistant member of the actual machine) extracted from the plant is acquired. In the creep test, by applying a predetermined stress (for example, X MPa) at a predetermined temperature (for example, 900 ° C.) to the catalyst pipe main body 11 removed from the plant, the time required for breaking the catalyst pipe main body 11 ( The break time of the actual machine is obtained.

  The Larson mirror parameter at fracture (a Larson mirror parameter at break) when the rupture time is obtained at the heat-resistant member creep test step S1 is derived at the fracture-time Larson mirror parameter derivation step S2. Based on the time required for the catalyst tube body 11 to break (the breaking time of the actual machine) and the temperature (for example, 900 ° C.) at this time, the Larson mirror parameters at break are derived using the following relational expression (3) Be done.

The Larson Miller parameter (LMP) satisfies the relationship of the following equation.
LMP = T × (C + log (t)) / 1000 (3)
T is a temperature (absolute temperature (K)) at the time of creep test of the catalyst tube main body 11 to be estimated, C is a material constant of the catalyst tube main body 11 to be estimated, and t is a catalyst tube to be estimated It is an operation (use) time of the main body 11. In the Larsen mirror parameter derivation step S2 at the time of breakage of the heat-resistant member, the breakage time acquired at the heat-resistant member creep test step S1 is used as the t.

  Design showing a relationship between a Larson mirror parameter at break (for example, a plot in FIG. 2) and a Larson mirror parameter which is initial data of the catalyst pipe main body 11 and a stress in the creep strength diagram acquisition step S3 of the heat resistant member Based on the creep strength diagram (for example, the slope of the straight line A shown in FIG. 2), the Larson mirror parameters at break (for example, a diagram) at break stress (test conditions (the predetermined stress in the creep test step S1) X) YA) shown in 2, that is, the creep strength diagram of the heat-resistant member is obtained. As the breaking stress X, it is preferable to use a stress (design stress) at which the catalyst pipe body 11 breaks at the time of design.

  In the equivalent average operating temperature estimation step S4, the equivalent average operating temperature of the catalyst tube main body 11 subjected to the above test is estimated. For this estimation of the equivalent average operating temperature, it is preferable to use, for example, an equivalent average operating temperature estimation method shown in FIG. 3 and FIG. This equivalent average operating temperature estimation method is, as shown in FIG. 3, a replica creation step S11, a carbide image creation step S12, an image adjustment step S13, a carbide amount derivation step S14, and a current Larson mirror parameter derivation step S15. And an equivalent average operating temperature estimation step S16.

  In the replica creation step S11, a replica is created by a conventional replica method. In this replica preparation step S11, a replica to which the surface texture of the catalyst tube main body 11 is transferred is prepared. It is preferable to use a film as the replica. Before transferring the surface texture of the catalyst tube main body 11 to the replica, it is preferable to make the surface texture appear to the catalyst tube main body 11 by polishing and etching.

  In the carbide image forming step S12, an image of a carbide is formed from the film to which the surface structure of the catalyst tube main body 11 obtained in the replica forming step S11 is transferred. The image of carbide is preferably an image of primary carbide (primary carbide image) or an image of secondary carbide (secondary carbide image), and more preferably both of these. This is because it is possible to more reliably estimate the operating temperature of the catalyst tube main body 11, which will be described later in detail. Each image is created by conventional image editing software. Primary carbides are carbides that crystallize along dendrite boundaries during solidification. Secondary carbides are precipitates dispersed and precipitated in grains with high temperature aging.

  In the image adjustment step S13, the carbide image created in the carbide image creation step S12 is adjusted to create an image in which extraction of carbides is easy. If the carbide image is a primary carbide image, the primary carbide image is adjusted to create an image that facilitates extraction of the primary carbide. When the carbide image is a secondary carbide image, the secondary carbide image is adjusted to create an image that facilitates extraction of secondary carbides. It is preferable to use a binarization process as a method of adjusting a carbide image (a primary carbide image, a secondary carbide image). When the carbide image is a primary carbide image, the primary carbide image is binarized to create a primary carbide binary image. When the carbide image is a secondary carbide image, the secondary carbide image is binarized to form a secondary carbide binarized image. Thereby, the carbide (the primary carbide binary image, the secondary carbide binary image) obtained from the carbide binary image (primary carbide binary image, secondary carbide binary image) obtained by binarizing the carbide image (primary carbide image, secondary carbide image) Extraction of primary carbides and secondary carbides) is facilitated.

  In the carbide amount deriving step S14, the carbide amount is derived based on the image obtained in the image adjustment step S13. If the image obtained in the image adjustment step S13 is a primary carbide binary image, the primary carbide amount is derived based on the primary carbide binary image. If the image obtained in the image adjustment step S13 is a secondary carbide binarized image, the amount of secondary carbides is derived based on the secondary carbide binarized image. When the image obtained in the image adjustment step S13 is a primary carbide binary image and a secondary carbide binary image, the primary carbide amount is derived based on the primary carbide binary image, and The secondary carbide content is derived based on the secondary carbide binary image. As the amount of carbides, the image obtained in the image adjustment step S13 is image-analyzed, the number of carbides is measured, and the number density of carbide particles obtained by converting per unit area, and the image obtained in the image adjustment step S13 It is preferable to use the area ratio of carbide obtained by analysis and measuring the area of carbide and converting it per unit area, and it is more preferable to use both the particle number density of the carbide and the area ratio of the carbide.

  Carbide amount derivation step using the correlation diagram (master curve) of Larson mirror parameters and carbide amount (grain number density of carbide, area ratio of carbide) created in advance in current Larson mirror parameter derivation step S15 The current Larson mirror parameters corresponding to the amount of carbides (number density of particles of carbide, area ratio of carbides) obtained in S14 are obtained. The amount of carbides is preferably the amount of primary carbides or the amount of secondary carbides described above.

  For example, in the case where the carbide amount obtained in the carbide amount deriving step S14 is the particle number density of carbides, the figure is created using a correlation diagram (master curve) of Larson mirror parameters and particle number density of carbides prepared beforehand. As shown in FIG. 4 (a), the current Larson mirror parameters corresponding to the particle number density of the carbide obtained in the carbide amount deriving step S14 are acquired. When the amount of carbides obtained in the step of deriving the amount of carbides is the area ratio of carbides, the correlation curve (master curve) of the Larson mirror parameter and the area ratio of carbides prepared in advance is used as shown in FIG. As shown in FIG. 5, the current Larson mirror parameter corresponding to the area ratio of the carbide obtained in the carbide amount deriving step S14 is acquired.

  In the equivalent average operating temperature estimation step S16, using the above-mentioned relational expression (3), based on the current Larson mirror parameters obtained in the current Larson mirror parameter derivation step S15 and the known operation time, the relational expression (3) The T in the equation (3) is estimated (derived) as an equivalent average operating temperature. The known operation time corresponds to the operation time of the catalyst tube body 11 in the plant. In the equivalent average operating temperature estimation step S16, the current Larson mirror parameter is substituted into LMP of the relational expression (3), and the known operating time is substituted into t of the relational expression (3). It will be.

  In the remaining life deriving step S5, the remaining life of the catalyst tube main body 11 described above is derived. Creep Strength Diagram of Heat-Resistant Member The creep strength diagram of the heat-resistant member acquired in the step S3 and the above-mentioned relational expression (3) based on the equivalent average operating temperature derived in the equivalent average operating temperature estimation step S4 (S16) Thus, the operation (use) time t can be obtained. This operation time t corresponds to the remaining life. Therefore, the remaining life of the catalyst tube main body 11 is derived by the above-mentioned relational expression (3) based on the creep strength diagram of the heat-resistant member and the equivalent average operating temperature.

  In the entire life deriving step S6, the entire life of the catalyst tube main body 11 described above is derived. The total life of the catalyst pipe body 11 described above is derived by determining the sum of the remaining life obtained in the remaining life deriving step S5 and the operation (use) time of the catalyst pipe body 11 described above. .

  In the total life Larson mirror parameter derivation step S7, the total life obtained in the total life derivation step S6 and the above-mentioned equivalent average operating temperature estimation step S4 (S16) using the above-mentioned relational expression (3) Based on the equivalent average operating temperature, the full life Larson mirror parameters (eg, YB shown in FIG. 2) are derived.

  In the initial creep strength diagram derivation step S8, the initial creep strength of the catalyst pipe main body 11 is derived based on the total life Larson mirror parameters of the catalyst pipe main body 11 derived in the whole life Larson mirror parameter derivation step S7. Design creep strength diagram (for example, the slope of the straight line A shown in FIG. 2) showing the relationship between Larson mirror parameters and stress, which are initial data of the catalyst tube main body 11, used in the creep strength diagram acquisition step S3 of heat resistant member Is used to derive an initial creep strength diagram (for example, a straight line B shown in FIG. 2) based on the total life Larson mirror parameters (for example, YB shown in FIG. 2) derived in the whole life Larson mirror parameter derivation step S7. Is preferred.

  Therefore, according to the present embodiment, the rupture time of the catalyst pipe main body 11, which is a heat-resistant member (aged heat-resistant member) used in a real machine, is acquired, and the Larson mirror parameters at break are derived. The creep strength diagram of the catalyst tube main body 11 is acquired based on the designed creep strength diagram, and the equivalent average operating temperature is estimated by the nondestructive test, and the creep strength diagram of the catalyst tube main body 11 and the equivalent average operating temperature Based on the equation (3), the remaining life is derived, and the remaining life and the operation time of the catalyst pipe main body 11 in the actual unit are summed to derive the total life, and the equation (3) is used to derive the total life. Using the design creep strength diagram based on the total life Larson mirror parameters based on the total life and the equivalent average operating temperature; It can be derived initial creep strength diagram in the. Therefore, the initial creep strength of the heat-resistant member can be rapidly estimated by a relatively simple operation.

  A carbide image is created from the replica obtained in the replica creation step S11, the image is adjusted (for example, binarization processing) as necessary, the amount of carbide is derived from the image, and the amount of carbide derived in advance is created The Larson mirror parameters are derived using the master curve which is a correlation diagram between the amount of carbides and the Larson mirror parameters, and based on the derived Larson mirror parameters and operation (use) time, the Larson mirror parameters and absolute temperature (equivalent average The equivalent average operating temperature during operation (during use) can be derived using the relational expression (3) between the operation temperature) and the operation (use) time. This makes it possible to estimate the operating temperature, which has conventionally been unknown, in a nondestructive and relatively simple operation. Further, even if there is a temperature fluctuation during operation, the equivalent average operating temperature can be derived, so that the initial creep strength of the heat-resistant member considering creep deformation can be estimated based on the equivalent average operating temperature. .

  When the carbide image is an image of a primary carbide, an image of a secondary carbide, or both of them, the amount of carbides can be reliably derived, and the operating temperature of the catalyst tube main body 11 in a relatively simple operation Can be estimated more reliably.

  Since the heat-resistant member is a catalyst pipe used for reforming natural gas, the initial creep strength of the catalyst pipe can be reliably estimated by a relatively simple operation.

Second Embodiment
The remaining life estimation method of the heat-resistant member according to the second embodiment of the present invention will be described based on FIG. 3, FIG. 4 and FIG.
In the present embodiment, the description overlapping with the above-described method for estimating the initial creep of the heat-resistant member is appropriately omitted.
In the method of estimating the lifetime of a heat-resistant member according to the present embodiment, as in the method of estimating the initial creep strength of a heat-resistant member described above, for example, several hundred collectors connected to each of a plurality of hot collectors provided in a natural gas reformer The case where the present invention is applied to a plurality of catalyst tubes consisting of

  The remaining life estimation method of the heat-resistant member according to the present embodiment is, as shown in FIG. 6, a current Larson mirror parameter derivation step S21, an equivalent average operating temperature estimation step S22, a total life derivation step S23, and a remaining life derivation And step S24.

  In the present Larson mirror parameter derivation step S21, the heat input received during operation of the catalyst pipe main body 11 mounted in the plant being operated by the nondestructive test is derived as a Larson mirror parameter. The current Larson mirror parameters are preferably derived using, for example, steps S11 to S15 in the procedure for estimating the equivalent average operating temperature shown in FIG. 3 and described above. That is, the current Larson mirror parameters may be derived through the replica creation step S11, the carbide image creation step S12, the image adjustment step S13, the carbide amount derivation step S14, and the current Larson mirror parameter derivation step S15. preferable.

  In the equivalent average operating temperature estimation step S22, the equivalent average operation (use) temperature of the catalyst tube main body 11 described above is estimated. The equivalent average operating temperature of the catalyst tube main body 11 is based on the current Larson mirror parameter derived in the current Larson mirror parameter derivation step S21 and the operating time in the above-mentioned plant, by the above-mentioned relational expression (3) It is preferable to derive.

  In the overall life deriving step S23, the overall life of the catalyst tube main body 11 described above is derived. The entire life of the catalyst tube main body 11 is, for example, based on the equivalent average operating temperature estimated in the equivalent average operating temperature estimation step S22, the initial creep strength of the catalyst tube main body 11 of the actual machine, and the known operating stress. It is preferable to derive by the relational expression (3) of The initial creep strength of the catalyst tube main body 11 is preferably derived, for example, by the method of estimating the initial creep strength of the heat-resistant member according to the first embodiment described above.

  In the remaining life deriving step S24, the remaining life of the catalyst tube main body 11 described above is derived. The remaining life of the catalyst tube main body 11 is derived by obtaining the difference between the total life derived in the entire life deriving step S23 and the operation (use) time of the catalyst tube main body 11 described above.

  Therefore, according to the present embodiment, when the initial creep strength of the catalyst pipe main body 11 mounted in the plant in operation is known, the current Larson mirror parameters derived by the nondestructive test and the catalyst pipe main body 11 The equivalent average operating temperature is estimated by the above-mentioned relational expression (3) based on the use (operation) time of the vehicle, and the entire life is derived based on the equivalent average operating temperature, the initial creep strength and the known operating stress. The remaining life of the catalyst tube main body 11 can be derived based on the entire life and the use (operation) time of the catalyst tube main body 11. Therefore, the remaining life of the heat-resistant member can be quickly estimated by a relatively simple operation.

[Other embodiments]
In the above, the method for estimating the initial creep strength of a heat resistant member for obtaining the initial creep strength by extracting the catalyst pipe main body 11 which is one heat resistant member from the plant under operation and acquiring the breaking stress of the actual machine was explained. However, it is also possible to extract the catalyst pipe main bodies 11 which are heat resistant members from the plant in operation and obtain the initial stage creep strength by obtaining the fracture stress of the actual machine with respect to them. is there. In this case, by acquiring the lower limit value in the creep strength diagram acquisition step S3 of the heat resistant member, the initial creep strength of the heat resistant member which is finally derived can be estimated low, and it is mounted in the plant under operation. Safety of the catalyst tube body can be secured more reliably.

  Although the case of deriving the carbide amount based on the image obtained in the image adjustment step S13 has been described above, based on the carbide image (for example, primary carbide image, secondary carbide image) created in the carbide image creation step S12 It is also possible to derive the amount of carbides.

  In the Larson mirror parameter derivation steps S15 and S21, a correlation diagram (master curve) between the Larson mirror parameters and the particle number density of carbides or the area ratio of carbides is the particle number density of one carbide or the area ratio of carbides When two or more Larson mirror parameters are indicated, it is preferable to derive the Larson mirror parameters respectively. It is possible to derive the range of the estimated equivalent average temperature during operation (in use) by using the derived Larson mirror parameters, and to evaluate the remaining life of the heat-resistant member considering creep deformation based on this temperature range. It is because

  In the above description, the case of using the catalyst pipe as the estimation target of the initial creep strength and the remaining life has been described, but the initial creep strength estimation of the heat-resistant member whose form of primary carbide and secondary carbide in the structure changes when held at high temperature It is also possible to apply to life estimation. Even in such a case, the same effects as the above-described method for estimating the initial creep strength of the heat-resistant member or the method for estimating the remaining life can be obtained.

  Although the embodiment carried out to confirm the effect of the method for estimating the initial creep strength of a heat-resistant member according to the present invention will be described below, the present invention is limited to the following embodiments described based on various data. It is not a thing.

[Confirmation test]
In this test, the initial creep strength of the catalyst pipe main body which is the heat resistant member was derived in the procedure of the method of estimating the initial creep strength of the heat resistant member according to the embodiment described above. The reference stress value S1 is 15.6 MPa.

  Regarding the specimen 1, the rupture time of the actual machine is acquired in the heat resistant member creep test (acquisition of rupture time at test temperature and stress) step S1 shown in FIG. 1 and described above and the Larson mirror parameter derivation step S2 at rupture of the heat resistant member. At the same time, the Larson mirror parameters at break are derived. By performing this operation a plurality of times (six times), as shown in FIG. 7, six plots can be obtained in a graph showing the relationship between the Larson mirror parameters and the stress. Here, the initial creep strength is related to the entire life of the catalyst tube main body which is a heat resistant member, and a design creep strength diagram (straight line L1 showing a relationship between Larson mirror parameters and stress, which are initial data of the catalyst tube main body). Stress and the Larson mirror parameter are in inverse proportion to each other. Therefore, in the test body 1, in the creep strength diagram acquisition step S3 of the heat-resistant member, P1 (P1 (15.6 MPa) based on Z1, the inclination of the straight line L1, and the breaking stress value S1 (15.6 MPa) in FIG. LMP: 33.2) is derived.

  Subsequently, the equivalent average operating temperature (1019 ° C.) is estimated in the equivalent average operating temperature estimation step S4 (steps S11 to S16) shown in FIGS. 1 and 3 and described above, and the remaining life (625) is determined in the remaining life derivation step S5. Time) is derived. Then, on the basis of the operation time (22,277 hours) in the actual machine, the total life (22,902 hours) is derived in the above-mentioned overall life deriving step S6 shown in FIG. Next, in the all-life Larson mirror parameter derivation step S7 shown in FIG. 1 and described above, the all-life Larson mirror parameter P1a (based on the overall life and the equivalent average operating temperature, using the above-mentioned relational expression (3) LMP: 35.2) is derived. Next, in the initial creep strength diagram derivation step S8 shown in FIG. 1 and described above, the initial creep strength diagram L1a is derived using the whole life Larson mirror parameter P1a and the designed creep strength diagram (the slope of the straight line L1). Be done.

  In the test body 2 as well as in the test body 1 described above, P2 (LMP: 34.4) is derived based on Z2, the slope of the straight line L2, and the breaking stress value S1 (15.6 MPa). Ru. Subsequently, the equivalent average operating temperature (975 ° C.) is derived, and the remaining life (46108 hours) is derived. Then, based on the operation time (22,277 hours) in the actual machine, the entire life (68,385 hours) is derived. A total life Larson mirror parameter P2a (LMP: 34.6) is derived based on the total life and the equivalent average operating temperature using the above-mentioned relational expression (3). Next, based on the total life Larson mirror parameter P2a, an initial creep strength diagram L2a is derived using the designed creep strength diagram (the slope of the straight line L2).

  Also in the test body 3, P3 (LMP: 34.8) is derived based on Z3, the slope of the straight line L3, and the breaking stress value S1 (15.6 MPa) in the same manner as the test body 1 described above Ru. Subsequently, the equivalent average operating temperature (901 ° C.) is derived, and the remaining life (5543397 hours) is derived. Then, the entire life (5521 120 hours) is derived based on the operation time (22 277 hours) in the actual machine. A total life Larson mirror parameter P3a (LMP: 34.8) is derived based on the total life and the equivalent average operating temperature using the above-mentioned relational expression (3). Next, based on the total life Larson mirror parameter P3a, an initial creep strength diagram L3a is derived using the designed creep strength diagram (slope of the straight line L3).

  Thus, according to the method for estimating the initial creep strength of a heat-resistant member according to the first embodiment shown in FIGS. 1, 3 and 4 and described above, it is possible to estimate the initial creep strength of the test bodies 1, 2 and 3. It became clear.

11 catalyst tube body 12 short piece 13 pigtail 14 catalyst tube 15 hot collector 21 mixed gas (H ₂ O, CH ₄ )
22 Product gas (H ₂ , H ₂ O, CO, CO ₂ )

Claims (8)

A method of estimating the initial creep strength of a heat-resistant member, comprising
A rupture time acquisition step of acquiring a rupture time by performing a creep test on the heat-resistant member at a predetermined temperature and stress;
A Larson mirror parameter-at-rupture deriving step of deriving a Larson mirror parameter at rupture using the following relational expression (1) based on the rupture time of the heat-resistant member and the predetermined temperature;
The creep strength diagram of the heat-resistant member is acquired based on the design creep strength diagram showing the relationship between the Larson mirror parameter at break, the Larson mirror parameter which is initial data of the heat-resistant member, and the stress in the heat-resistant member. A creep strength diagram acquisition step of the heat resistant member,
An equivalent average operating temperature estimation step of estimating an equivalent average operating temperature from a carbide state of the heat resistant member;
A remaining life deriving step of deriving the remaining life of the heat resistant member using the following relational expression (1) based on the creep strength diagram of the heat resistant member, the equivalent average operating temperature, and the known operating stress ,
An overall life deriving step of deriving the overall life of the heat resistant member based on the remaining life of the heat resistant member and the operation time of the heat resistant member;
An overall life Larson mirror parameter deriving step of deriving an overall life Larson mirror parameter using the following relational expression (1) based on the overall life of the heat resistant member and the equivalent average operating temperature;
An initial creep strength diagram deriving step of deriving an initial creep strength diagram of the heat resistant member using the design creep strength diagram based on the total life Larson mirror parameters; and a heat resistant member Initial creep strength estimation method.
LMP = T × (C + log (t)) / 1000 (1)
LMP is the Larson Miller parameter,
T is the absolute temperature (K),
C is a material constant of the heat-resistant member,
t is the operating time of the heat-resistant member. The method for estimating the initial creep strength of a heat-resistant member according to claim 1, wherein
In the equivalent average operating temperature estimation step, a replica to which the surface structure of the heat-resistant member is transferred is created, a carbide image is created based on the replica, a carbide amount is derived based on the carbide image, and the carbide amount is The present Larson mirror parameters are derived using the master curve which is a correlation diagram between the amount of carbides and the Larson mirror parameters created, and based on the present Larson mirror parameters and the operation time of the heat resistant member, A method of estimating the initial creep strength of a heat-resistant member, comprising: estimating an equivalent average operating temperature using the relational expression (1). The method for estimating the initial creep strength of a heat-resistant member according to claim 2, wherein
The method for estimating the initial creep strength of a heat-resistant member, wherein the carbide image is an image of a primary carbide, an image of a secondary carbide, or both of them. A method of estimating the initial creep strength of a heat-resistant member according to claim 2 or claim 3, wherein
The method for estimating the initial creep strength of a heat-resistant member, wherein the amount of carbides is at least one of grain number density of carbides and area ratio of carbides. A method of estimating initial creep strength of a heat-resistant member according to any one of claims 2 to 4,
The current Larson mirror parameters are derived using the amount of carbide derived based on the carbide binarized image created by binarizing the carbide image and using the master curve instead of the carbide image. A method of estimating the initial creep strength of a heat-resistant member characterized by A method of estimating initial creep strength of a heat-resistant member according to any one of claims 1 to 5,
The method of estimating the initial creep strength of a heat-resistant member, wherein the heat-resistant member is a catalyst pipe used for reforming natural gas. It is a remaining life estimating method of a heat resistant member which estimates the remaining life of the heat resistant member,
The heat input received by the current heat resistant member during operation is derived as a Larson mirror parameter by nondestructive testing,
Based on the current Larson mirror parameters of the heat-resistant member and the known operation time, the following equation (2) is used to estimate the equivalent average operating temperature,
The equivalent average operating temperature, the initial creep strength of the heat resistant member derived by the method of estimating the initial creep strength of the heat resistant member according to any one of claims 1 to 5, and the known operating stress Based on the following equation (2) to derive the total life,
A remaining life estimation method for a heat-resistant member, comprising: deriving a remaining life based on the total life and the operation time of the heat-resistant member.
LMP = T × (C + log (t)) / 1000 (2)
LMP is the current Larson mirror parameter of the heat resistant member,
T is the equivalent average operating temperature (absolute temperature (K)),
t is the operation time (total life). It is a remaining life estimation method of the heat-resistant member described in Claim 7, Comprising:
The said heat-resistant member is a catalyst pipe | tube used for reforming of natural gas. The remaining life estimation method of the heat-resistant member characterized by the above-mentioned.

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